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Preface Annex 1
CHALLENGES FOR REALIZING DEVELOPMENT OPPORTUNITIES
Many countries face high costs – economical, environmental and social – due to the presence of IAS. The financial and management costs associated with their eradication are astronomical and their proliferation affects the potential of countries to meet their development and environmental objectives. Resources spent on trying to control IAS could be redirected to other development initiatives, such as the implementation of the MDGs. This is an important reason to adopt approaches which control and prevent introductions.
Invasive alien species cost millions of US dollars annually in terms of lost revenue and expenditure on control measures. While the actual costs of IAS are unknown, they are believed to be substantial. The global economic costs of IAS are estimated by IUCN to be about US$400 000 million annually (UNEP 2003); IUCN also finds that IAS threaten the success of current and planned World Bank projects to the value of more than US$13 000 million (UNEP 2004).
Currently, Africa spends an estimated US$60 million annually on the control of IAS (CBD 2005). The African Ministerial Conference on the Environment (AMCEN) plans to raise a further US$265 million to fund various projects related to IAS in Africa over the next three to five years (UNEP 2004).
In South Africa, alien plant species now cover more than 10.1 million ha, threatening indigenous plants (ITC undated). (See Figure 2). Freshwater systems and the Cape Floral Kingdom (a global centre of biodiversity) are particularly at threat and the South African government therefore established the “Working for Water” programme. This programme seeks to remove IAS infestations from water catchment, and at the same time provide poverty relief (van Wilgen and others 1998). In South Africa, in addition to altering water-flow, IAS have had other important impacts on endemic biodiversity and ecosystem services. Nitrogen-fixing plants such as Acacia saligna alter the nitrogen cycle, impacting on native plants adapted to low nutrient conditions, such as, for example, many of the fynbos species. The costs associated with eradicating IAS, as shown in Box 6, have exceeded US 100 million.
In the Western Indian Ocean (WIO) countries, IAS pose a serious threat to forests and thus place biodiversity, including many endemics, at risk. Among these invasive woody species are Paraserianthes falcataria (Albizia), Adenanthera pavonia (Agati), Clidemia hirta (Creole name: Faux Watouk), Cinnamomum verum, Chrysobalanus icaco (Prune de France), Psidium cattleianum (wild guava), Syzygium jambos, Astonia macrophylla (Bois jaune) and Tabebuia pallida (Calice du pape) (IUCN/SSG/ISSG). In addition to the costs to biodiversity, governments incur substantial financial and management costs. In the Seychelles, for example, the Ministry of Environment is involved in a programme for the eradication of IAS, including those listed below, and the replanting of indigenous species; public education is seen as an important aspect of this (Ministry of Environment Seychelles, undated):
Across Africa, IAS in the genus Striga have a direct impact on local livelihoods, affecting more than 100 million people and as much as 40 per cent of arable land in the savannahs. The cost of eradicating it is reportedly between US$7-13 000 million annually (UNEP 2004). These invasives stunt maize plant growth by attacking the roots and sucking nutrients and water (Ithula 2004) and thus in addition to the direct financial costs have implications for food security.
SMALL ISLAND DEVELOPING STATES
While islands may not be more susceptible to invasions by alien species than continental landmasses, they are, however, considered to be particularly vulnerable to the impacts of such invasions (CBD 2003 and IUCN/SSC/ISSG 2001). On islands, IAS are now on a par with habitat loss as the lead driver of species extinctions over the last 20 years (Baillie and others 2004).
Important opportunities exist for effective control for terrestrial IAS. These can be effectively controlled through customs and border monitoring; these measures have greater potential for success on islands than in countries that share boundaries (IUCN/SSC/ ISSG 2001 and Wittenberg and Cock 2001). In terms of responses on islands, research shows that the experience of one island country can be invaluable in managing IAS on another island even where there are major differences in climate and ecological systems. Key similarities such as the role and nature of trade may be significant. Areas where a cooperative initiative on island IAS may be especially valuable include (IUCN/SSG/ISSG 2001):